Current nuclear imaging systems are limited by poor spatial resolution, low count rate, poor photon utilization (gamma ray collection efficiency) and lack of three-dimensional capability. Improvement in any of these areas would have important clinical ramifications. Improved resolution, for example, would allow earlier detection of small filling defects and improved morphological differentiation of benign and malignant nodules. Improved quantum utilization (collection efficiency) would permit a reduction in patient dose or, if the count rate allowed, reduction in exposure time. Improved tomography could aid in the perception of low-contrast lesions. The research proposed here is directed at each of these areas of potential improvement. Three major projects are involved, including research into gamma ray image forming elements, and detection of the gamma ray image. Our attack on the image detector part of the problem is based on the observation that a large improvement in both resolution and count rate is possible if we limit ourselves to detectors capable of determining only one coordinate of the scintillation location. Two specific approaches to the exploitation of this dimensionality tradeoff are proposed. To fully utilize the gains afforded by either of these new detectors, we need an imaging aperture that gives high resolution together with good quantum utilization, while not requiring a two-dimensional detector. Two such apertures are proposed here.